This invention relates generally to waveform matching for identification purposes, and more specifically, it relates to waveform matching as it is used, for example, to identify documents which are used in data processing.
One suitable application for this invention relates to the handling of documents such as bank checks or drafts and other media which are coded or printed in magnetic ink. For example, bank checks have printed thereon a MICR line (Magnetic Ink Character Recognition) which line includes, for example, an account number, bank number, and check number which are printed in magnetic ink.
In one system of banking, the record media such as bank checks and deposit slips, for example, are processed in an Entry or a First Pass Unit (FPU) where certain operations are performed. The record media are generally processed in groups or "batches" of about 250-300 checks per batch, for example. The MICR data is read from the checks for a batch of checks and the data read may be stored in a memory unit. At some subsequent operation, for example, the monetary amount of each check in the batch of checks is read or obtained by mechanical (character recognition) or manual methods, and the monetary amount is stored in a memory unit.
Continuing with the batch processing of bank checks, for example, the monetary amount for each check is then encoded or printed on the corresponding check and some physical sorting of the batch of checks may be done after the encoding is completed. The encoding and sorting is done, for example, at a second unit, referred to hereinafter as a Second Pass Unit (SPU). At this time, it is extremely important that the monetary amount for each check in the batch get actually encoded or printed on the correct check. In other words, the monetary amounts which are stored in memory, for example, must be encoded on the correct check. At the SPU, the MICR data is read again to provide a second reading which is compared with the first reading obtained from the FPU to make sure that the checks are properly identified and have remained in the same order. Assuming that the second reading from the SPU agrees with the first reading from the FPU, indicating that the check is properly identified, the monetary amount for that check is then encoded thereon, in the example described. Thereafter, the checks may be sorted by the SPU by various criteria as is conventionally done.
One type of comparison or verification performed with MICR data is to compare the second reading of each character of a MICR line of data with each corresponding character obtained from the first reading, as in the example described above; however, this type of comparison improperly or falsely rejects correct readings in about 1% of the comparisons. Naturally, when thousands of documents are to be sorted, even a small false rejection rate of 1%, for example, becomes cumbersome to correct manually. Another system for comparing entails matching the entire waveform received from the first MICR reading at the FPU with the entire waveform received from the second MICR reading at the SPU. Because the check transport mechanisms in the FPU and the SPU move the checks at different actual speeds even though the transports are designed to operate at the same speed, the correlation between first and second readings becomes progressively unsynchronized near the end-of-the-reading scans.